Pressure in gases and liquids
Liquid Pressure
Liquid pressure is the force that a liquid exerts on the walls or bottom of its container.
It is caused by the weight of the liquid and acts in all directions.
The deeper you go, the greater the pressure — because more liquid is above that point.
Example: When you dive deeper into a swimming pool, you feel more pressure on your ears — that’s liquid pressure increasing with depth.
Gas Pressure
Gas pressure is the force that gas particles exert on the walls of their container when they collide with them.
It happens because gas particles move fast in all directions and hit the walls many times each second.
If the gas is heated, particles move faster → more collisions → higher pressure.
If the gas is cooled or the container’s volume increases, pressure goes down.
Example: When you pump air into a football, the air molecules hit the inside walls more often — that’s what makes it firm and full.